1. Field of the Invention
The present invention relates to the field of computer tomography (CT), and, more particularly, to a thoracic cage coordinate system for denoting pathology locations in lung CT volume data.
2. Description of the Related Art
With the development of multi-slice computer tomography (“CT”) scanners, computer-aided diagnosis (“CAD”) algorithms and software can provide functionalities that make reading CT volume data more convenient and effective. An important task of CAD software is to record pathology locations as a basic reporting functionality. For example, the locations of lung nodules, which indicate possible lung cancer, may be recorded after they are found by physicians or by a CAD module.
Currently available recording schemes are generally not satisfactory. Internally, they record pathology locations using a patient coordinate system (i.e., x, y and z coordinates). When displayed for physicians, such pathology locations are coarsely referenced even with respect to simple lung anatomic structures, such as lung lobes. Because the patient coordinate system depends largely on patient pose and translations, it is generally inaccurate.
Thus, it would be advantageous to provide a coordinate system that is independent of patient pose and translations. Further, the coordinate system should be stable over small deformations of the patient's body or inhalation level.